[yocto] Issue when integrating different bsp-layers on a single bblayers.conf

[Trevor Woerner]

Hi Iván,

On Thu 2018-06-07 @ 04:39:11 PM, Iván Castell wrote:
> When setting the "build" directory with a bblayers.conf customized for a
> single platform, each platform builds the image recipe properly.
> 
> However, when I have integrated all bsp-layers in a single bblayers.conf,
> the compilation of some platforms has been broken.

This is a problem that comes up fairly often, and is a bug with the BSP layer
itself. All BSP layers are supposed to be created so that they work well when
intermixed with other BSP layers, but often they don't. See Angstrom:

	http://www.angstrom-distribution.org/

> The specific problem is this: one bsp layer (meta-rockchip +
> meta-rockchip-extra) defines a recipes-graphics/mesa/mesa_%.bbappend with
> this content inside:

I am the maintainer of the non-vendor meta-rockchip layer:

	https://git.yoctoproject.org/cgit/cgit.cgi/meta-rockchip/

The fact you mention this problem and meta-rockchip-extra implies to me that
you're using the vendor-provided meta-rockchip and meta-rockchip-extra:

	https://github.com/rockchip-linux/meta-rockchip
	https://github.com/rockchip-linux/meta-rockchip-extra

The problem is, the vendor is only interested in their own hardware, so to
them there's no reason to ever mix their BSP layer with any other BSP layer.
There's no interest on their part to "play well" with others or to check
whether their layers comply with community guidelines.

As a person who likes OpenEmbedded as a whole, I try my best to make sure any
layer I'm interested in plays well within the entire OpenEmbedded ecosystem.
However, because mali graphics are currently all binary blobs and projects
like Lima and Panfrost aren't yet ready for prime-time, there isn't much
support yet for _accelerated_ graphics in the non-vendor layer.

>     - Can you suggest a fix to solve this issue?

Fix the problem in the layer by using MACHINE-specific OVERRIDES and submit
a pull request to the owners. However, I've noticed there haven't been any
updates to their OE layers in the past 4 months or more, so I can't help
wonder if they've abandoned them.

Out of curiosity, which MACHINE(s) are you interested in?

Best regards,
	Trevor